Cannula-based Versus Needle-based Subcision for Posttraumatic Atrophic Facial Scars

Inclusion Criteria: * Adult Patients (\> 20-years old) with posttraumatic facial scar Exclusion Criteria: * other types of scars (e.g; postacne scars), pregnancy, lactation, bleeding or coagulation disorders, liability for keloid formation, history of kobnerization, and patients with systemic diseases (cardiac, chronic renal diseases, chronic liver diseases, asthma and hypertension) at the time of recruitment.